Stereodivergent Attached‐Ring Synthesis via Non‐Covalent Interactions: A Short Formal Synthesis of Merrilactone A

A strategy to control the diastereoselectivity of bond formation at a prochiral attached‐ring bridgehead is reported. An unusual stereodivergent Michael reaction relies on basic vs. Lewis acidic conditions and non‐covalent interactions to control re‐ vs. si‐ facial selectivity en route to fully substituted attached‐rings. This divergency reflects differential engagement of one rotational isomer of the attached‐ring system. The successful synthesis of an erythro subtarget diastereomer ultimately leads to a short formal synthesis of merrilactone A. An unusual stereodivergent Michael reaction relies on basic vs. Lewis acidic conditions and non‐covalent interactions to control re‐ vs. si‐ facial selectivity en route to fully substituted attached‐rings. This differential engagement of one rotational isomer of an attached‐ring system leads to a short formal synthesis of merrilactone A.